The objectives of this Core are: to maintain a resource laboratory for measuring eicosanoid and cytokine concentrations in biologic fluids; to share costly resources required for studying the biochemistry of arachidonic acid metabolites and cytokines; and to provide consultation to SCOR investigators regarding suitable methods and experimental designs for the collection and measurement of these mediators. Using equilibrium radioimmunoassay techniques, the laboratory will measure prostaglandins (PGE2, PGF2delta, PGD2, and the stable hydrolysis products of PGI2 (6-Keto- PGF1delta) and thromboxane A2 (thromboxane B2, TxB2), 12 and 5 hydroxyeicosatetraenoic acid (12 and 5 HETE), and the leukotrienes C4 (LTC4) and D4 (LTD4) in lung washings and cell culture fluids. Employing solid phase immunoassays in concert with biological assays, cytokines present in biological fluids will be quantitated by uniform methodology. A central core laboratory will, therefore, consolidate costs, achieve efficient processing of samples, and provide quality control and direct consultation for investigators participating in SCOR research activities.